Pressure sensors are used in automotive vehicles for a variety of purposes, for example, for sensing the vacuum pressure at the intake manifold of a vehicle's engine. Typically such sensors include a pressure sensitive element, such as a piezoresistive silicon element that is integrated with silicon circuitry in a monolithic silicon chip. Generally, the sensor needs to be calibrated to permit compensation for the variations that tend to occur between individual pressure sensitive elements. To this end, it is advantageous to include as part of the integrated circuit, a conditioning network that permits custom adjustment of the output parameters of individual sensors. This conditioning network typically is a network of parallel resistors, of which some may be selectively removed from the integrated circuit by opening fusible links in the network.
In prior art pressure sensors, such fusible links have typically been opened optically by irradiation of selected fusible links with laser pulses to burn open such links selectively. This proves difficult in a manufacturing environment where such adjustment is preferably made.